geometry app question...

10152017, 05:34 AM
Post: #1




geometry app question...
I'm trying to draw a circle, tangent to 3 lines using incircle().
I have 3 lines defined as: GA: line(y=(2*x+5)) GB: line(y=(2*x4)) GC: line(y=(7*x+5)) and then I tried incircle as in: GD: incircle(GA,GB,GC) It draws the lines fine, but there is no circle on the plot screen.... What am I doing wrong? Thanks Donald 

10152017, 06:06 AM
Post: #2




RE: geometry app question...
Oncalc help says incircle uses 3 Points rather than 3 lines.
Arno 

10152017, 06:43 AM
Post: #3




RE: geometry app question...
You are right....but that's kinda screwed up, as it's supposed to draw a circle that is a tangent to 3 sides of a triangle. When I specify 3 points, I don't see the edges of the triangle....just the vertices and a circle in the middle somewhere....i.e. You can't see the tangents.


10152017, 07:06 AM
(This post was last modified: 10152017 07:09 AM by Didier Lachieze.)
Post: #4




RE: geometry app question...
Starting from your 3 lines you can then define the triangle vertices and draw the circle :
GA:= line(y = (2*x+5)); GB:= line(y = (2*x4)); GC:= line(y = (7*x+5)); GD:= single_inter(GA,GB); GE:= single_inter(GB,GC); GG:= single_inter(GA,GC); GH:= incircle(GD,GE,GG); If you have just 3 points GA,GB,GC you can draw the triangle with triangle(GA,GB,GC) 

10152017, 07:22 AM
Post: #5




RE: geometry app question...
Cool! Thank you!
D 

10162017, 02:07 PM
(This post was last modified: 10162017 02:08 PM by Brad Barton.)
Post: #6




RE: geometry app question...
(10152017 07:06 AM)Didier Lachieze Wrote: Starting from your 3 lines you can then define the triangle vertices and draw the circle : I tried this out today, and it looks pretty good in the plot screen. However when I try to generate the coordinates of the intersection of the circle and any one of the tangent lines, I get an imaginary result. Does this mean that the circle and the lines don't truly intersect? 

10162017, 08:25 PM
(This post was last modified: 10162017 08:27 PM by Arno K.)
Post: #7




RE: geometry app question...
If I remember correctly, points in geometry are represented by complex numbers.
Arno 

10162017, 08:28 PM
Post: #8




RE: geometry app question...  
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